Corncob particles that are not sterilized or sanitized (hereinafter referred to as traditional corncob) and used as animal bedding worldwide have relatively high microbial populations. High levels of microbial contamination increase the likelihood that disease-causing microorganisms (pathogens) may be present. Pathogens in bedding materials can be harmful to animals by infection of wounds or by causing digestive or respiratory problems and thereby confounding results of experiments. Consequently, many animal research facilities control against pathogens in their animal bedding by either purchasing bedding that has been irradiated or autoclaving bedding that has not been irradiated.
In the field of animal management, specifically that of laboratory animals, such as rodents, all environmental conditions to which the animals are exposed must be tightly controlled to prevent contaminations of the animals by the external environment and/or nosocomial contamination.
Research animals are becoming more valuable because many disease models are expensive and time-consuming to develop. Some longitudinal studies require data collection on the same animals over their lifetimes. Preventing nosocomial infection is paramount in maintaining the integrity of the research design and in preserving valuable laboratory stock for continued study.
Most research institutions invest substantial resources to keep these valuable animal assets safe. Microbial safety and cost factors are major issues associated with use of bedding materials for laboratory animals. Traditional corncob after it enters the lab animal facility leaves open the possibility that pathogenic bacteria are introduced to the facility in storage and handling before sterilization efforts. Using irradiated or pre-sanitized corncob essentially eliminates that risk because the corncob arrives at the facility with near sterile characteristics. However, the cost of irradiated corncob bedding can triple that of non-sanitized bedding, and autoclaving is widely understood to be costly, especially when energy costs are taken into account. The high costs of irradiating or autoclaving present an opportunity for applied science to achieve the same degree or better of near-sterility at a significantly lower cost.
The destruction of pathogenic bacteria, fungi and viruses in corncob particles can be achieved by rigorous chemical or physical methods required to destroy bacterial endospores. This is true because bacterial endospores exhibit the highest resistance to chemicals, heat or irradiation compared to other microorganisms including viruses.
Another, less common, method for sterilizing food is the tyndallization process, named after the 19th century scientist John Tyndall. Tyndallization essentially consists of heating the substance for 15 minutes for three days in a row (usually by boiling it). During the waiting periods over the three days, the substance being sterilized is kept at a warm room temperature; i.e., a temperature that is conducive to germination of the spores. On the second day most of the spores that survived the first day will have germinated into bacterial cells. These cells will be killed by the second day's heating. The third day kills bacterial cells from late-germinating spores. This process requires considerable time, and the material being treated must be maintained at the proper conditions over the entire 3-day period. Further, the tyndallization process is not considered reliably effective.
It is challenging to destroy bacterial endospores with interventions other than those previously mentioned which are costly, cumbersome, difficult to scale up, and raise questions about reliability. One approach to kill the endospores with greater practicability is to render them more susceptible to the inactivation method. One way to decrease spore resistance is to induce spore germination.
Accordingly, the overall goal of the present invention is to provide a novel process to substantially reduce or eliminate populations of bacterial endospores in corncob particles by exploiting their vulnerable state—after germination. Once germinated, spores have decreased resistance to chemicals, heat or irradiation.
Therefore, it is a primary object, feature, or advantage of the present invention to improve upon the state of the art.
It is a further objective, feature or advantage of the present invention to provide methods for substantially reducing or eliminating populations of bacterial endospores in fibrous material.
It is a further objective, feature or advantage of the present invention to provide methods for substantially reducing or eliminating populations of bacterial endospores in plant-fiber-rich (PFR) material by exploiting the vulnerable state of those spores when stimulated to germinate.
It is a further objective, feature or advantage of the present invention to provide reliable methods for reducing or eliminating populations of bacterial endospores in PFR material, wherein the process can be completed in less than one day, and preferably less than five hours.
It is a further objective, feature or advantage of the present invention to provide reliable methods for reducing or eliminating populations of bacterial endospores in PFR material, wherein the product of the process is a dry PFR material.
It is a further objective, feature or advantage of the present invention to provide PFR material, for example corncob particles, that has been sanitized by a process that substantially reduces or eliminates populations of bacterial endospores in corncob particles by exploiting the vulnerable state of those spores when stimulated to germinate.
It is a further objective, feature or advantage of the present invention to provide reliable methods for reducing or eliminating viruses in PFR material, wherein the product of the process is a dry fiber-rich material.